Production of carbon black



March 14, 1944. CQNNER PRODUCTION OF CARBON BLACK 2 Sheets-Sheet 1 Filed May 5, 1941 II II \I II u u u fiewr Zeozzarzi/Zbzzzez: @yMZOM ZDWpM a! '5.

Patented Mar. 14, 1944 PRODUCTION OF CARBON BLACK Leonard M. Conner, Sunray, Tex., assignor to Continental Carbon Company, a corporation of Delaware Application May 5, 1941, Serial No. 392,021

4 Claims.

This invention relates to a method of producing carbon black and more particularly to a method by which the production of carbon black may be increased from a given plant while maintaining the product more uniform.

The customary method of manufacturing car- I bon black is to burn hydrocarbon gases under a system of steelchannels upon which the carbon is deposited. In practice many thousands of lava-tipped gas flames are so placed with referenc to the steel channels that the flame from each of the burners impinges directly upon a steel channel and spreads over the bottom surface thereof. The channels are moved slowly back and forth over the burners. The channels themselves are stationed in the upper portion of a burner building which normall accommodates a considerable number of parallel steel channels. For example, a typical building may be ten feet wide, one hundred eighty feet long and contain ten parallel steel channels, each approximately eight inche in cross section. The whole channel system is mounted on a track which is slowly reciprocated over the burners, the movement being approximately .eight feet in fifteen minutes. The burners are located at intervals of about eight inches and are so adjusted as to produce a luminous-type flame of fish-tail shape with the flat sides of the flame at right angles to the longitudinal edges of the channel.

With so many burners in a single building the amount of air available for combustion is largely controlled by the natural draft openings in the top and bottom of the building. In general practice the amount of air available below the burners is so adjusted that the flame has the appearance of being slightly deficient in air. As a result of this method the top portion of the building above the flames contains a. blanket of smoke which hangs in the upper portion of the building and generally extends down to and over the flames, partially obscuring them. If too little air issupplied the smoke blanket will drop so low that the flames aresmothered. On the other hand, if there is too much air the blanket lifts above the flames" and these then burn brightly without producing much carbon.

The quality of carbon black produced, as indicated by the usefulness of the product for its desired functions, primarily in mixing at other periods, is seriously affected by the combustion conditions in the system. A properly balanced, slightly smothered combustion produces. not only the most carbon black but the best carbon black.

The use of the present invention has resulted in commercial production of a greater quantity of carbon black from a given unit in a given time, and has at the same time decreased the variation in the quality of the carbon black so as to produce very much less low grade material.

The combustion operation, depending as it does upon natural drafts, is extremely susceptible to changes in th draft. These changes may be effected by a number of elements. A heavy rain has the same effect on the combustion conditions of a carbon black plant as a hard wind. In other words, the buildings cool and lighten up in a hard rain and also the same in a hard wind. In both cases more gas will be put through the plant by operation of the control. Of more frequent importance are the diurnal changes in temperature, which, in many localities producing natural gas, are as much as 3040 F. on the average. The ordinary carbon black plant has many buildings of the type just described, and it has not proved practical to readjust the drafts with every change in weather conditions. Furthermore, it has not proved economical to provide drafts which can be easily controlled. The burner structures are usually very crude affairs and draft control would have to be by very crude methods. The draft is not the only factor controlling combustion conditions, and the present invention is designed to control combustion conditions irrespective of draft conditions, but also will tend to maintain a substantially uniform draft under most circumstances.

The preferred form of the invention is to provide automatic means for providing more gas whenever th temperature at a predetermined point in the burner house falls below a predetermined value and less gas whenever it rises above this value.

The invention is illustrated in the drawings in which Figure 1 is a vertical section taken along the line I of Figure 3 showing a typical burner house, illustrated somewhat diagrammatic lly; Figure 2 is a schematic view showing the operation of applicants preferred control system; Figure 3 is a longitudinal section taken along the line 3-3 of Figure I, looking in the direction of the arrows; and Figure 4 shows a diagrammatic plan view of one arrangement of the gas feeding system.

As shown in the drawings, the burner house It! is made up of metal sheets H, loosely assembled to provide air. building is a series of 8" channel member I! beneath each of which is provided a row of lava- At an upper portion of the I tipped gas burners II to which gas is supplied through a piping system I4. Means are provided, but not shown, for reciprocating the channel members back and forth over the burners. Scraper blades I! are provided for each channel and a hopper l6 collects the carbon black scraped flame is to produce a smoky zone l8 in the upper portions of the building which extends in part over th flames themselves, but not sufficiently to'smother the combustion. The zone of heavy smoke terminates somewhat above the flames as indicated by the line I9.

In normal operation when controlled by the present invention, each burner tipsupplies ap-' proximately 82 cubic feet of; natural gas per day, this being an increase of approximately 5% over the amount burned per burner under the previous system. This control is accomplished in its preferred form by means of a heat-sensitive element which is stationed above one of the channel members I2. Preferably, a channel member is selected which is not the outermost member. In the present instance the third channel memher from the outside is selected and the heatsensitive element is mounted approximately 14 inches above it and extends longitudinally along the channel member. The longer theelement 20 the more accurate are the results, but in ordinary practice it is not essential "that the heatsensitive element be unduly extended. In practice an element approximately 20 feet in length has proved quite satisfactory.

The heat-sensitive element 20 is a-closed tube containing air or other gas and communicating through the tube 2| to the cylinder 22. This cylinder contains a liquid 23 and is provided in its upper portion with a vent opening 24 controlled by a valve 25. The liquid 23 communicates with the line,21.and with the diaphragm valve 28 which is secured to a frame 29 by means of the bolt ,30. A spring 3| is positioned around the bolt 30 and tends to push the diaphragm 32 downwardly against the pressure of the liquid 23.

Variations in pressure within the diaphragm I 28 are communicated to diaphragm valve 33 i which adjusts the throttle valve 34 in the by-pass line 35 which takes gas from the main'supply line H. The by-pass line 35 communicates with thethird diaphragm ,valve 36. A line 31 communicates with the other side of diaphragm 36. Adjustments of the throttle valve 34 control the pressure differential on th valve 36 which in turn controls the setting of the main control valve 26.

The pressure of the gas within the tube 20 is adjusted to produce optimum operations at a given time. Thereafter it the temperature on the element rises, pressure therein also rises. This iscommunicated to the gas control valve 26-and diminishes the amount of gas delivered to the burners. It has been found generally satisfactory to use only one such control in a'series of buildings, but an element may be used in each building if desired.

On the other hand, if the temperature on the 'tube 20 falls, the pressure therein also falls and the gas control valve 26 is operated to increase the flow of gas to the burners. It has been found that under all normal operations no control of the draft need be made, the control being limited to increasing or decreasing the amount of gas combustion conditions in the chamber do not depend upon any one burner but upon the group effect of the whole set. v

The combination of a gas filled element, in direct contact with the high temperature zone, and a liquid filled element, controlled thereby, is of particular value in a system as extensive as is found in carbon black plants. The use of an entire communicating system filled with gas would be inadvisable because of the fact that the gas, being compressible, loses its eifect with distance. On the other hand, it is desirable to have a highly expanslble material in the high, temperature zone. The present system combines an incompressible liquid control with a highly expansible gas control,

In Figure 4 a simplified system for a plant oi forty-two burner buildings, in which only two controls are employed, is diagrammatically illustrated.

The line 50 is a header'which is connected by a number of pipes 6| to the burners in each oi the burner houses 52. These are arranged twenty-one on each side of the header, each building being approximately 180 feet long by 10 feet wide. Gas is supplied to the header 60 through two supply lines 63 and 64, one of which is connected to the header as shown at 66 about one quarter of the distance from one end to the other, and the other header is connected at a point l6 similarly located with respect to the other end of theheader, The supply of gas is then controlled by the valves 26a and 26b, each of which is in turn controlled by a temperature responsive system such as heretofore described.

The valve 26a is controlled by a temperature responsive element in one of the twenty-one buildings on its side of the header, preferably a building at least three buildings from the end of the row. The valve 26b is similarly controlled bya temperature responsive element in a similarly located building on its side of the header.

With this type of system it is of course possible for one of the valves 26a and 26b to be supplying and desire to secure by lation system, the method which comprises automatically regulating the fiow of gas to the bumers in response to temperature-sensitive means, to produce a greater flow of gas to the burners when the temperature at points adjacent impingement surfaces in the combustion zone falls too low, and a smaller flow of gas to the burners when the temperature is too high.

2. In the production of carbon black, in a sysreducing the flow of gas to burners when the In temperature is too high.

3. The method as set forth in claim 1 in which the regulation is carried out by pressure means directly responsive to temperature conditions at a predetermined point in the combustion system.

4. The method as set forth in claim 2, in which the flow of gas is controlled automatically in response to pressure in an elongated pipe in the combustion zone.

LEONARD M. CONNER. 

